addad Memtable::clear

src/memtable/mod.rs

@@ -36,7 +36,7 @@ where
 #[derive(Default)]
 pub struct Memtable {
     #[doc(hidden)]
-    items: SkipMap<InternalKey, UserValue>,
+    pub items: SkipMap<InternalKey, UserValue>,
 
     /// Approximate active memtable size
     ///
@@ -45,6 +45,13 @@ pub struct Memtable {
 }
 
 impl Memtable {
+    /// Clears the memtable.
+    pub fn clear(&mut self) {
+        self.items.clear();
+        self.approximate_size
+            .store(0, std::sync::atomic::Ordering::Release);
+    }
+
     /// Creates an iterator over all items.
     pub fn iter(&self) -> impl DoubleEndedIterator<Item = InternalValue> + '_ {
         self.items.iter().map(|entry| InternalValue {

src/tree/mod.rs

@@ -177,6 +177,7 @@ impl AbstractTree for Tree {
         })?;
 
         for segment in segments {
+            log::trace!("releasing sealed memtable {}", segment.metadata.id);
             sealed_memtables.remove(segment.metadata.id);
         }
 
@@ -239,13 +240,13 @@ impl AbstractTree for Tree {
         log::trace!("rotate: acquiring active memtable write lock");
         let mut active_memtable = self.lock_active_memtable();
 
+        log::trace!("rotate: acquiring sealed memtables write lock");
+        let mut sealed_memtables = self.lock_sealed_memtables();
+
         if active_memtable.is_empty() {
             return None;
         }
 
-        log::trace!("rotate: acquiring sealed memtables write lock");
-        let mut sealed_memtables = self.lock_sealed_memtables();
-
         let yanked_memtable = std::mem::take(&mut *active_memtable);
         let yanked_memtable = Arc::new(yanked_memtable);